314734-24-2Relevant academic research and scientific papers
Stereocontrolled synthesis of Z-dienes via an unexpected pericyclic cascade rearrangement of 5-amino-2,4-pentadienals
Steinhardt, Sarah E.,Silverston, Joel S.,Vanderwal, Christopher D.
, p. 7560 - 7561 (2008/12/22)
Donor-acceptor dienes known as Zincke aldehydes, which derive readily from the ring-opening reactions of pyridinium salts with secondary amines, undergo a fascinating thermal rearrangement reaction to afford Z-α,β,γ,δ-unsaturated amides with excellent stereoselectivity. Efficient, stereocontrolled access to Z-trisubstituted alkenes with two different substitution patterns is possible in three steps beginning with the appropriately substituted pyridine derivative. Preliminary studies have shown that both the amide and the monosubstituted alkene termini can be selectively functionalized. Ease of access, generality of scope, and facile product manipulation render this process attractive for the synthesis of complex polyenes. Copyright
8-Phenyl-10,10a-dihydropyrido[1,2-a]azepines by 1,7-electrocyclization of conjugated pyridinium ylides - rationalization of the periselectivity
Marx, Karsten,Eberbach, Wolfgang
, p. 2063 - 2068 (2007/10/03)
Base treatment of the pyridinium bromides 11a-e gives rise to the formation of the dihydropyridoazepines 14a-e as the only monomolecular products. The reaction takes place by initial deprotonation to the ylides 12, which undergo 8π-electrocyclization affording the seven-membered-ring systems; no products of a dipolar 6π-cyclization were detected. On the basis of quantum mechanical calculations a rationalization of the periselectivity of the electrocyclization process is given.
